OpenCloudOS-Kernel/arch/x86/entry
Linus Torvalds 475d4df827 v6.6-vfs.fchmodat2
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZOXT7QAKCRCRxhvAZXjc
 ort3AP0VIK/oJk5skgjpinQrCfvtVz0XOtawuBtn0f1weIfb6AD9Hg1rqOKnQD5z
 dkvn3xaEr3gPOVzqU5SvFwVoCM0cMwA=
 =24Ha
 -----END PGP SIGNATURE-----

Merge tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull fchmodat2 system call from Christian Brauner:
 "This adds the fchmodat2() system call. It is a revised version of the
  fchmodat() system call, adding a missing flag argument. Support for
  both AT_SYMLINK_NOFOLLOW and AT_EMPTY_PATH are included.

  Adding this system call revision has been a longstanding request but
  so far has always fallen through the cracks. While the kernel
  implementation of fchmodat() does not have a flag argument the libc
  provided POSIX-compliant fchmodat(3) version does. Both glibc and musl
  have to implement a workaround in order to support AT_SYMLINK_NOFOLLOW
  (see [1] and [2]).

  The workaround is brittle because it relies not just on O_PATH and
  O_NOFOLLOW semantics and procfs magic links but also on our rather
  inconsistent symlink semantics.

  This gives userspace a proper fchmodat2() system call that libcs can
  use to properly implement fchmodat(3) and allows them to get rid of
  their hacks. In this case it will immediately benefit them as the
  current workaround is already defunct because of aformentioned
  inconsistencies.

  In addition to AT_SYMLINK_NOFOLLOW, give userspace the ability to use
  AT_EMPTY_PATH with fchmodat2(). This is already possible with
  fchownat() so there's no reason to not also support it for
  fchmodat2().

  The implementation is simple and comes with selftests. Implementation
  of the system call and wiring up the system call are done as separate
  patches even though they could arguably be one patch. But in case
  there are merge conflicts from other system call additions it can be
  beneficial to have separate patches"

Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=17eca54051ee28ba1ec3f9aed170a62630959143;hb=a492b1e5ef7ab50c6fdd4e4e9879ea5569ab0a6c#l35 [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c?id=718f363bc2067b6487900eddc9180c84e7739f80#n28 [2]

* tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  selftests: fchmodat2: remove duplicate unneeded defines
  fchmodat2: add support for AT_EMPTY_PATH
  selftests: Add fchmodat2 selftest
  arch: Register fchmodat2, usually as syscall 452
  fs: Add fchmodat2()
  Non-functional cleanup of a "__user * filename"
2023-08-28 11:25:27 -07:00
..
syscalls arch: Register fchmodat2, usually as syscall 452 2023-07-27 12:25:35 +02:00
vdso x86/mm: Fix VDSO and VVAR placement on 5-level paging machines 2023-08-09 13:38:48 -07:00
vsyscall x86: Allow atomic MM_CONTEXT flags setting 2023-03-16 13:08:39 -07:00
Makefile x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y 2022-08-04 12:23:50 +02:00
calling.h x86/retbleed: Add fine grained Kconfig knobs 2022-06-29 17:43:41 +02:00
common.c X86 entry code related updates: 2021-06-29 12:44:51 -07:00
entry.S x86/bugs: Add retbleed=ibpb 2022-06-27 10:34:00 +02:00
entry_32.S x86: Rewrite ret_from_fork() in C 2023-07-10 09:52:25 +02:00
entry_64.S x86: Fix kthread unwind 2023-07-20 23:03:50 +02:00
entry_64_compat.S - Add the call depth tracking mitigation for Retbleed which has 2022-12-14 15:03:00 -08:00
syscall_32.c x86/syscalls: Stop filling syscall arrays with *_sys_ni_syscall 2021-05-20 15:03:59 +02:00
syscall_64.c x86/syscalls: Stop filling syscall arrays with *_sys_ni_syscall 2021-05-20 15:03:59 +02:00
syscall_x32.c x86/syscalls: Stop filling syscall arrays with *_sys_ni_syscall 2021-05-20 15:03:59 +02:00
thunk_32.S x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y 2022-08-04 12:23:50 +02:00
thunk_64.S x86/entry: Move thunk restore code into thunk functions 2023-06-07 09:54:45 -07:00